In comparison with complicated mathematic techniques geoinformation modeling of floods doesn`t need a fullset of statistic data. A practicability of using GIS arises when it`s necessary not to predict a flood but to model actual water spreading.By the example of Biysk a technique of geoinformation modeling of hazardous flood happened in Altai Krai inMay–June of 2014 and its consequences for local people is described in the article. Digital elevation model extracted by a photogrammetric method from a stereo pair of high resolution satellite imagery forms a basis of flood zones modeling.